Why some greens turn brown in historical paintings

Enticed by the brilliant green hues of copper acetate and copper resinate, some painters in the Renaissance period incorporated these pigments into their masterpieces. However, by the 18th century, most artists had abandoned the colors because of their tendency to darken with time. Now, researchers have uncovered the chemistry behind the copper pigments' color change.

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African evidence support Younger Dryas Impact Hypothesis

A team of scientists from South Africa has discovered evidence partially supporting a hypothesis that Earth was struck by a meteorite or asteroid 12,800 years ago, leading to global consequences including climate change, and contributing to the extinction of many species of large animals at the time of an episode called the Younger Dryas.

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Tale of two climate crises gives clues to the present

Figuring out what lies ahead for our species and our planet is one of the most pressing and challenging tasks for climate scientists. While models are very useful, there is nothing quite like Earth's history to reveal details about how oceans, animals, and plants respond to and recover from a warming world.

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How and when was carbon distributed on Earth?

A magma ocean existing during the core formation is thought to have been highly depleted in carbon due to its high-siderophile (iron loving) behavior. Thus, most of the carbon forming the atmosphere and life on Earth may have been delivered by a carbon-rich embryo after the core formation. However, a new high-pressure experiment has shown that previous studies may have overestimated the amount of carbon partitioning to the core.

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Is theory on Earth's climate in the last 15 million years wrong?

A key theory that attributes the climate evolution of the Earth to the breakdown of Himalayan rocks may not explain the cooling over the past 15 million years, according to a new study. The study could shed more light on the causes of long-term climate change. It centers on the long-term cooling that occurred before the recent global warming tied to greenhouse gas emissions from humanity.

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New evidence of the Sahara's age

The Sahara Desert is vast, generously dusty, and surprisingly shy about its age. New research looking into what appears to be dust that the Sahara blew over to the Canary Islands is providing the first direct evidence from dry land that the age of the Sahara matches that found in deep-sea sediments: at least 4.6 million years old.

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Grand ideas, global reverberations: Grand Canyon at its 6 millionth anniversary

Etched onto the steep walls of Arizona's 6,000-foot-deep, 277-mile-long Grand Canyon are clues that chronicle the sweeping changes the region has experienced during the past two billion years. The canyon's colorful layers narrate tales of ancient environments come and gone, from lofty mountain ranges and tropical seas to a Saharan-scale desert that once stretched across much of western North America.

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Dust from a giant asteroid crash caused an ancient ice age

About 466 million years ago, long before the age of the dinosaurs, the Earth froze. The seas began to ice over at the Earth's poles, and new species evolved with the new temperatures. The cause of this ice age was a mystery, until now: a new study argues that the ice age was caused by global cooling, triggered by extra dust in the atmosphere from a giant asteroid collision in outer space.

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